1. Field of the Invention
This invention relates primarily to a method and means for utilizing waste heat and more particularly to a method and means for utilizing the heat of molten slag.
2. Description of the Prior Art
In the blast furnace and steel making operation, slag is formed by the action of flux upon the gangue of ore and by the oxidation of impurities in the metal. The molten slag is separated from the molten metal and poured into ladles or cars and transported to a pit area where it is discharged for solidification and further processed for granulation or otherwise made into a friable product for non-metallurgical uses such as aggregate for concrete, macadam, and bituminous products or soil conditioners. The temperature of the molten slag when discharged from the blast furnace is approximately 3000.degree. F. and is cooled to solidification temperature for further processing. The heat dissippated during this temperature drop is wasted in the prior art procedure of handling molten slag.
FIG. 1 diagramatically illustrates the prior art practice. The slag car is filled with molten slag during the furnace tapping and transported on tracks to slag dumps for solidification. After solidification and sufficient cooling, slag breaking equipment is used to break up the solidified slag into transportable pieces which are then collected and placed in scrap cars for transportation to a conveyor run. The conveyor run is provided with means to magnetically separate the iron content of the slag pieces. The slag pieces continue to be conveyed to a crusher mill where it is particulated for further use in the slag industry. The recovered iron is collected and returned as raw material charge. During this operation, the molten slag continues to be transported to another dump area which is being filled while the first slag dump area is cleared of solidified slag. When this operation is completed, the slag crushing equipment is moved to the now solidified second slag dump area for similar removal and crushing operation.